ASR_BASE
Change-Id: Icf3719cc0afe3eeb3edc7fa80a2eb5199ca9dda1
diff --git a/marvell/linux/tools/testing/selftests/kvm/lib/sparsebit.c b/marvell/linux/tools/testing/selftests/kvm/lib/sparsebit.c
new file mode 100644
index 0000000..031ba3c
--- /dev/null
+++ b/marvell/linux/tools/testing/selftests/kvm/lib/sparsebit.c
@@ -0,0 +1,2086 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Sparse bit array
+ *
+ * Copyright (C) 2018, Google LLC.
+ * Copyright (C) 2018, Red Hat, Inc. (code style cleanup and fuzzing driver)
+ *
+ * This library provides functions to support a memory efficient bit array,
+ * with an index size of 2^64. A sparsebit array is allocated through
+ * the use sparsebit_alloc() and free'd via sparsebit_free(),
+ * such as in the following:
+ *
+ * struct sparsebit *s;
+ * s = sparsebit_alloc();
+ * sparsebit_free(&s);
+ *
+ * The struct sparsebit type resolves down to a struct sparsebit.
+ * Note that, sparsebit_free() takes a pointer to the sparsebit
+ * structure. This is so that sparsebit_free() is able to poison
+ * the pointer (e.g. set it to NULL) to the struct sparsebit before
+ * returning to the caller.
+ *
+ * Between the return of sparsebit_alloc() and the call of
+ * sparsebit_free(), there are multiple query and modifying operations
+ * that can be performed on the allocated sparsebit array. All of
+ * these operations take as a parameter the value returned from
+ * sparsebit_alloc() and most also take a bit index. Frequently
+ * used routines include:
+ *
+ * ---- Query Operations
+ * sparsebit_is_set(s, idx)
+ * sparsebit_is_clear(s, idx)
+ * sparsebit_any_set(s)
+ * sparsebit_first_set(s)
+ * sparsebit_next_set(s, prev_idx)
+ *
+ * ---- Modifying Operations
+ * sparsebit_set(s, idx)
+ * sparsebit_clear(s, idx)
+ * sparsebit_set_num(s, idx, num);
+ * sparsebit_clear_num(s, idx, num);
+ *
+ * A common operation, is to itterate over all the bits set in a test
+ * sparsebit array. This can be done via code with the following structure:
+ *
+ * sparsebit_idx_t idx;
+ * if (sparsebit_any_set(s)) {
+ * idx = sparsebit_first_set(s);
+ * do {
+ * ...
+ * idx = sparsebit_next_set(s, idx);
+ * } while (idx != 0);
+ * }
+ *
+ * The index of the first bit set needs to be obtained via
+ * sparsebit_first_set(), because sparsebit_next_set(), needs
+ * the index of the previously set. The sparsebit_idx_t type is
+ * unsigned, so there is no previous index before 0 that is available.
+ * Also, the call to sparsebit_first_set() is not made unless there
+ * is at least 1 bit in the array set. This is because sparsebit_first_set()
+ * aborts if sparsebit_first_set() is called with no bits set.
+ * It is the callers responsibility to assure that the
+ * sparsebit array has at least a single bit set before calling
+ * sparsebit_first_set().
+ *
+ * ==== Implementation Overview ====
+ * For the most part the internal implementation of sparsebit is
+ * opaque to the caller. One important implementation detail that the
+ * caller may need to be aware of is the spatial complexity of the
+ * implementation. This implementation of a sparsebit array is not
+ * only sparse, in that it uses memory proportional to the number of bits
+ * set. It is also efficient in memory usage when most of the bits are
+ * set.
+ *
+ * At a high-level the state of the bit settings are maintained through
+ * the use of a binary-search tree, where each node contains at least
+ * the following members:
+ *
+ * typedef uint64_t sparsebit_idx_t;
+ * typedef uint64_t sparsebit_num_t;
+ *
+ * sparsebit_idx_t idx;
+ * uint32_t mask;
+ * sparsebit_num_t num_after;
+ *
+ * The idx member contains the bit index of the first bit described by this
+ * node, while the mask member stores the setting of the first 32-bits.
+ * The setting of the bit at idx + n, where 0 <= n < 32, is located in the
+ * mask member at 1 << n.
+ *
+ * Nodes are sorted by idx and the bits described by two nodes will never
+ * overlap. The idx member is always aligned to the mask size, i.e. a
+ * multiple of 32.
+ *
+ * Beyond a typical implementation, the nodes in this implementation also
+ * contains a member named num_after. The num_after member holds the
+ * number of bits immediately after the mask bits that are contiguously set.
+ * The use of the num_after member allows this implementation to efficiently
+ * represent cases where most bits are set. For example, the case of all
+ * but the last two bits set, is represented by the following two nodes:
+ *
+ * node 0 - idx: 0x0 mask: 0xffffffff num_after: 0xffffffffffffffc0
+ * node 1 - idx: 0xffffffffffffffe0 mask: 0x3fffffff num_after: 0
+ *
+ * ==== Invariants ====
+ * This implementation usses the following invariants:
+ *
+ * + Node are only used to represent bits that are set.
+ * Nodes with a mask of 0 and num_after of 0 are not allowed.
+ *
+ * + Sum of bits set in all the nodes is equal to the value of
+ * the struct sparsebit_pvt num_set member.
+ *
+ * + The setting of at least one bit is always described in a nodes
+ * mask (mask >= 1).
+ *
+ * + A node with all mask bits set only occurs when the last bit
+ * described by the previous node is not equal to this nodes
+ * starting index - 1. All such occurences of this condition are
+ * avoided by moving the setting of the nodes mask bits into
+ * the previous nodes num_after setting.
+ *
+ * + Node starting index is evenly divisible by the number of bits
+ * within a nodes mask member.
+ *
+ * + Nodes never represent a range of bits that wrap around the
+ * highest supported index.
+ *
+ * (idx + MASK_BITS + num_after - 1) <= ((sparsebit_idx_t) 0) - 1)
+ *
+ * As a consequence of the above, the num_after member of a node
+ * will always be <=:
+ *
+ * maximum_index - nodes_starting_index - number_of_mask_bits
+ *
+ * + Nodes within the binary search tree are sorted based on each
+ * nodes starting index.
+ *
+ * + The range of bits described by any two nodes do not overlap. The
+ * range of bits described by a single node is:
+ *
+ * start: node->idx
+ * end (inclusive): node->idx + MASK_BITS + node->num_after - 1;
+ *
+ * Note, at times these invariants are temporarily violated for a
+ * specific portion of the code. For example, when setting a mask
+ * bit, there is a small delay between when the mask bit is set and the
+ * value in the struct sparsebit_pvt num_set member is updated. Other
+ * temporary violations occur when node_split() is called with a specified
+ * index and assures that a node where its mask represents the bit
+ * at the specified index exists. At times to do this node_split()
+ * must split an existing node into two nodes or create a node that
+ * has no bits set. Such temporary violations must be corrected before
+ * returning to the caller. These corrections are typically performed
+ * by the local function node_reduce().
+ */
+
+#include "test_util.h"
+#include "sparsebit.h"
+#include <limits.h>
+#include <assert.h>
+
+#define DUMP_LINE_MAX 100 /* Does not include indent amount */
+
+typedef uint32_t mask_t;
+#define MASK_BITS (sizeof(mask_t) * CHAR_BIT)
+
+struct node {
+ struct node *parent;
+ struct node *left;
+ struct node *right;
+ sparsebit_idx_t idx; /* index of least-significant bit in mask */
+ sparsebit_num_t num_after; /* num contiguously set after mask */
+ mask_t mask;
+};
+
+struct sparsebit {
+ /*
+ * Points to root node of the binary search
+ * tree. Equal to NULL when no bits are set in
+ * the entire sparsebit array.
+ */
+ struct node *root;
+
+ /*
+ * A redundant count of the total number of bits set. Used for
+ * diagnostic purposes and to change the time complexity of
+ * sparsebit_num_set() from O(n) to O(1).
+ * Note: Due to overflow, a value of 0 means none or all set.
+ */
+ sparsebit_num_t num_set;
+};
+
+/* Returns the number of set bits described by the settings
+ * of the node pointed to by nodep.
+ */
+static sparsebit_num_t node_num_set(struct node *nodep)
+{
+ return nodep->num_after + __builtin_popcount(nodep->mask);
+}
+
+/* Returns a pointer to the node that describes the
+ * lowest bit index.
+ */
+static struct node *node_first(struct sparsebit *s)
+{
+ struct node *nodep;
+
+ for (nodep = s->root; nodep && nodep->left; nodep = nodep->left)
+ ;
+
+ return nodep;
+}
+
+/* Returns a pointer to the node that describes the
+ * lowest bit index > the index of the node pointed to by np.
+ * Returns NULL if no node with a higher index exists.
+ */
+static struct node *node_next(struct sparsebit *s, struct node *np)
+{
+ struct node *nodep = np;
+
+ /*
+ * If current node has a right child, next node is the left-most
+ * of the right child.
+ */
+ if (nodep->right) {
+ for (nodep = nodep->right; nodep->left; nodep = nodep->left)
+ ;
+ return nodep;
+ }
+
+ /*
+ * No right child. Go up until node is left child of a parent.
+ * That parent is then the next node.
+ */
+ while (nodep->parent && nodep == nodep->parent->right)
+ nodep = nodep->parent;
+
+ return nodep->parent;
+}
+
+/* Searches for and returns a pointer to the node that describes the
+ * highest index < the index of the node pointed to by np.
+ * Returns NULL if no node with a lower index exists.
+ */
+static struct node *node_prev(struct sparsebit *s, struct node *np)
+{
+ struct node *nodep = np;
+
+ /*
+ * If current node has a left child, next node is the right-most
+ * of the left child.
+ */
+ if (nodep->left) {
+ for (nodep = nodep->left; nodep->right; nodep = nodep->right)
+ ;
+ return (struct node *) nodep;
+ }
+
+ /*
+ * No left child. Go up until node is right child of a parent.
+ * That parent is then the next node.
+ */
+ while (nodep->parent && nodep == nodep->parent->left)
+ nodep = nodep->parent;
+
+ return (struct node *) nodep->parent;
+}
+
+
+/* Allocates space to hold a copy of the node sub-tree pointed to by
+ * subtree and duplicates the bit settings to the newly allocated nodes.
+ * Returns the newly allocated copy of subtree.
+ */
+static struct node *node_copy_subtree(struct node *subtree)
+{
+ struct node *root;
+
+ /* Duplicate the node at the root of the subtree */
+ root = calloc(1, sizeof(*root));
+ if (!root) {
+ perror("calloc");
+ abort();
+ }
+
+ root->idx = subtree->idx;
+ root->mask = subtree->mask;
+ root->num_after = subtree->num_after;
+
+ /* As needed, recursively duplicate the left and right subtrees */
+ if (subtree->left) {
+ root->left = node_copy_subtree(subtree->left);
+ root->left->parent = root;
+ }
+
+ if (subtree->right) {
+ root->right = node_copy_subtree(subtree->right);
+ root->right->parent = root;
+ }
+
+ return root;
+}
+
+/* Searches for and returns a pointer to the node that describes the setting
+ * of the bit given by idx. A node describes the setting of a bit if its
+ * index is within the bits described by the mask bits or the number of
+ * contiguous bits set after the mask. Returns NULL if there is no such node.
+ */
+static struct node *node_find(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep;
+
+ /* Find the node that describes the setting of the bit at idx */
+ for (nodep = s->root; nodep;
+ nodep = nodep->idx > idx ? nodep->left : nodep->right) {
+ if (idx >= nodep->idx &&
+ idx <= nodep->idx + MASK_BITS + nodep->num_after - 1)
+ break;
+ }
+
+ return nodep;
+}
+
+/* Entry Requirements:
+ * + A node that describes the setting of idx is not already present.
+ *
+ * Adds a new node to describe the setting of the bit at the index given
+ * by idx. Returns a pointer to the newly added node.
+ *
+ * TODO(lhuemill): Degenerate cases causes the tree to get unbalanced.
+ */
+static struct node *node_add(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep, *parentp, *prev;
+
+ /* Allocate and initialize the new node. */
+ nodep = calloc(1, sizeof(*nodep));
+ if (!nodep) {
+ perror("calloc");
+ abort();
+ }
+
+ nodep->idx = idx & -MASK_BITS;
+
+ /* If no nodes, set it up as the root node. */
+ if (!s->root) {
+ s->root = nodep;
+ return nodep;
+ }
+
+ /*
+ * Find the parent where the new node should be attached
+ * and add the node there.
+ */
+ parentp = s->root;
+ while (true) {
+ if (idx < parentp->idx) {
+ if (!parentp->left) {
+ parentp->left = nodep;
+ nodep->parent = parentp;
+ break;
+ }
+ parentp = parentp->left;
+ } else {
+ assert(idx > parentp->idx + MASK_BITS + parentp->num_after - 1);
+ if (!parentp->right) {
+ parentp->right = nodep;
+ nodep->parent = parentp;
+ break;
+ }
+ parentp = parentp->right;
+ }
+ }
+
+ /*
+ * Does num_after bits of previous node overlap with the mask
+ * of the new node? If so set the bits in the new nodes mask
+ * and reduce the previous nodes num_after.
+ */
+ prev = node_prev(s, nodep);
+ while (prev && prev->idx + MASK_BITS + prev->num_after - 1 >= nodep->idx) {
+ unsigned int n1 = (prev->idx + MASK_BITS + prev->num_after - 1)
+ - nodep->idx;
+ assert(prev->num_after > 0);
+ assert(n1 < MASK_BITS);
+ assert(!(nodep->mask & (1 << n1)));
+ nodep->mask |= (1 << n1);
+ prev->num_after--;
+ }
+
+ return nodep;
+}
+
+/* Returns whether all the bits in the sparsebit array are set. */
+bool sparsebit_all_set(struct sparsebit *s)
+{
+ /*
+ * If any nodes there must be at least one bit set. Only case
+ * where a bit is set and total num set is 0, is when all bits
+ * are set.
+ */
+ return s->root && s->num_set == 0;
+}
+
+/* Clears all bits described by the node pointed to by nodep, then
+ * removes the node.
+ */
+static void node_rm(struct sparsebit *s, struct node *nodep)
+{
+ struct node *tmp;
+ sparsebit_num_t num_set;
+
+ num_set = node_num_set(nodep);
+ assert(s->num_set >= num_set || sparsebit_all_set(s));
+ s->num_set -= node_num_set(nodep);
+
+ /* Have both left and right child */
+ if (nodep->left && nodep->right) {
+ /*
+ * Move left children to the leftmost leaf node
+ * of the right child.
+ */
+ for (tmp = nodep->right; tmp->left; tmp = tmp->left)
+ ;
+ tmp->left = nodep->left;
+ nodep->left = NULL;
+ tmp->left->parent = tmp;
+ }
+
+ /* Left only child */
+ if (nodep->left) {
+ if (!nodep->parent) {
+ s->root = nodep->left;
+ nodep->left->parent = NULL;
+ } else {
+ nodep->left->parent = nodep->parent;
+ if (nodep == nodep->parent->left)
+ nodep->parent->left = nodep->left;
+ else {
+ assert(nodep == nodep->parent->right);
+ nodep->parent->right = nodep->left;
+ }
+ }
+
+ nodep->parent = nodep->left = nodep->right = NULL;
+ free(nodep);
+
+ return;
+ }
+
+
+ /* Right only child */
+ if (nodep->right) {
+ if (!nodep->parent) {
+ s->root = nodep->right;
+ nodep->right->parent = NULL;
+ } else {
+ nodep->right->parent = nodep->parent;
+ if (nodep == nodep->parent->left)
+ nodep->parent->left = nodep->right;
+ else {
+ assert(nodep == nodep->parent->right);
+ nodep->parent->right = nodep->right;
+ }
+ }
+
+ nodep->parent = nodep->left = nodep->right = NULL;
+ free(nodep);
+
+ return;
+ }
+
+ /* Leaf Node */
+ if (!nodep->parent) {
+ s->root = NULL;
+ } else {
+ if (nodep->parent->left == nodep)
+ nodep->parent->left = NULL;
+ else {
+ assert(nodep == nodep->parent->right);
+ nodep->parent->right = NULL;
+ }
+ }
+
+ nodep->parent = nodep->left = nodep->right = NULL;
+ free(nodep);
+
+ return;
+}
+
+/* Splits the node containing the bit at idx so that there is a node
+ * that starts at the specified index. If no such node exists, a new
+ * node at the specified index is created. Returns the new node.
+ *
+ * idx must start of a mask boundary.
+ */
+static struct node *node_split(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep1, *nodep2;
+ sparsebit_idx_t offset;
+ sparsebit_num_t orig_num_after;
+
+ assert(!(idx % MASK_BITS));
+
+ /*
+ * Is there a node that describes the setting of idx?
+ * If not, add it.
+ */
+ nodep1 = node_find(s, idx);
+ if (!nodep1)
+ return node_add(s, idx);
+
+ /*
+ * All done if the starting index of the node is where the
+ * split should occur.
+ */
+ if (nodep1->idx == idx)
+ return nodep1;
+
+ /*
+ * Split point not at start of mask, so it must be part of
+ * bits described by num_after.
+ */
+
+ /*
+ * Calculate offset within num_after for where the split is
+ * to occur.
+ */
+ offset = idx - (nodep1->idx + MASK_BITS);
+ orig_num_after = nodep1->num_after;
+
+ /*
+ * Add a new node to describe the bits starting at
+ * the split point.
+ */
+ nodep1->num_after = offset;
+ nodep2 = node_add(s, idx);
+
+ /* Move bits after the split point into the new node */
+ nodep2->num_after = orig_num_after - offset;
+ if (nodep2->num_after >= MASK_BITS) {
+ nodep2->mask = ~(mask_t) 0;
+ nodep2->num_after -= MASK_BITS;
+ } else {
+ nodep2->mask = (1 << nodep2->num_after) - 1;
+ nodep2->num_after = 0;
+ }
+
+ return nodep2;
+}
+
+/* Iteratively reduces the node pointed to by nodep and its adjacent
+ * nodes into a more compact form. For example, a node with a mask with
+ * all bits set adjacent to a previous node, will get combined into a
+ * single node with an increased num_after setting.
+ *
+ * After each reduction, a further check is made to see if additional
+ * reductions are possible with the new previous and next nodes. Note,
+ * a search for a reduction is only done across the nodes nearest nodep
+ * and those that became part of a reduction. Reductions beyond nodep
+ * and the adjacent nodes that are reduced are not discovered. It is the
+ * responsibility of the caller to pass a nodep that is within one node
+ * of each possible reduction.
+ *
+ * This function does not fix the temporary violation of all invariants.
+ * For example it does not fix the case where the bit settings described
+ * by two or more nodes overlap. Such a violation introduces the potential
+ * complication of a bit setting for a specific index having different settings
+ * in different nodes. This would then introduce the further complication
+ * of which node has the correct setting of the bit and thus such conditions
+ * are not allowed.
+ *
+ * This function is designed to fix invariant violations that are introduced
+ * by node_split() and by changes to the nodes mask or num_after members.
+ * For example, when setting a bit within a nodes mask, the function that
+ * sets the bit doesn't have to worry about whether the setting of that
+ * bit caused the mask to have leading only or trailing only bits set.
+ * Instead, the function can call node_reduce(), with nodep equal to the
+ * node address that it set a mask bit in, and node_reduce() will notice
+ * the cases of leading or trailing only bits and that there is an
+ * adjacent node that the bit settings could be merged into.
+ *
+ * This implementation specifically detects and corrects violation of the
+ * following invariants:
+ *
+ * + Node are only used to represent bits that are set.
+ * Nodes with a mask of 0 and num_after of 0 are not allowed.
+ *
+ * + The setting of at least one bit is always described in a nodes
+ * mask (mask >= 1).
+ *
+ * + A node with all mask bits set only occurs when the last bit
+ * described by the previous node is not equal to this nodes
+ * starting index - 1. All such occurences of this condition are
+ * avoided by moving the setting of the nodes mask bits into
+ * the previous nodes num_after setting.
+ */
+static void node_reduce(struct sparsebit *s, struct node *nodep)
+{
+ bool reduction_performed;
+
+ do {
+ reduction_performed = false;
+ struct node *prev, *next, *tmp;
+
+ /* 1) Potential reductions within the current node. */
+
+ /* Nodes with all bits cleared may be removed. */
+ if (nodep->mask == 0 && nodep->num_after == 0) {
+ /*
+ * About to remove the node pointed to by
+ * nodep, which normally would cause a problem
+ * for the next pass through the reduction loop,
+ * because the node at the starting point no longer
+ * exists. This potential problem is handled
+ * by first remembering the location of the next
+ * or previous nodes. Doesn't matter which, because
+ * once the node at nodep is removed, there will be
+ * no other nodes between prev and next.
+ *
+ * Note, the checks performed on nodep against both
+ * both prev and next both check for an adjacent
+ * node that can be reduced into a single node. As
+ * such, after removing the node at nodep, doesn't
+ * matter whether the nodep for the next pass
+ * through the loop is equal to the previous pass
+ * prev or next node. Either way, on the next pass
+ * the one not selected will become either the
+ * prev or next node.
+ */
+ tmp = node_next(s, nodep);
+ if (!tmp)
+ tmp = node_prev(s, nodep);
+
+ node_rm(s, nodep);
+ nodep = NULL;
+
+ nodep = tmp;
+ reduction_performed = true;
+ continue;
+ }
+
+ /*
+ * When the mask is 0, can reduce the amount of num_after
+ * bits by moving the initial num_after bits into the mask.
+ */
+ if (nodep->mask == 0) {
+ assert(nodep->num_after != 0);
+ assert(nodep->idx + MASK_BITS > nodep->idx);
+
+ nodep->idx += MASK_BITS;
+
+ if (nodep->num_after >= MASK_BITS) {
+ nodep->mask = ~0;
+ nodep->num_after -= MASK_BITS;
+ } else {
+ nodep->mask = (1u << nodep->num_after) - 1;
+ nodep->num_after = 0;
+ }
+
+ reduction_performed = true;
+ continue;
+ }
+
+ /*
+ * 2) Potential reductions between the current and
+ * previous nodes.
+ */
+ prev = node_prev(s, nodep);
+ if (prev) {
+ sparsebit_idx_t prev_highest_bit;
+
+ /* Nodes with no bits set can be removed. */
+ if (prev->mask == 0 && prev->num_after == 0) {
+ node_rm(s, prev);
+
+ reduction_performed = true;
+ continue;
+ }
+
+ /*
+ * All mask bits set and previous node has
+ * adjacent index.
+ */
+ if (nodep->mask + 1 == 0 &&
+ prev->idx + MASK_BITS == nodep->idx) {
+ prev->num_after += MASK_BITS + nodep->num_after;
+ nodep->mask = 0;
+ nodep->num_after = 0;
+
+ reduction_performed = true;
+ continue;
+ }
+
+ /*
+ * Is node adjacent to previous node and the node
+ * contains a single contiguous range of bits
+ * starting from the beginning of the mask?
+ */
+ prev_highest_bit = prev->idx + MASK_BITS - 1 + prev->num_after;
+ if (prev_highest_bit + 1 == nodep->idx &&
+ (nodep->mask | (nodep->mask >> 1)) == nodep->mask) {
+ /*
+ * How many contiguous bits are there?
+ * Is equal to the total number of set
+ * bits, due to an earlier check that
+ * there is a single contiguous range of
+ * set bits.
+ */
+ unsigned int num_contiguous
+ = __builtin_popcount(nodep->mask);
+ assert((num_contiguous > 0) &&
+ ((1ULL << num_contiguous) - 1) == nodep->mask);
+
+ prev->num_after += num_contiguous;
+ nodep->mask = 0;
+
+ /*
+ * For predictable performance, handle special
+ * case where all mask bits are set and there
+ * is a non-zero num_after setting. This code
+ * is functionally correct without the following
+ * conditionalized statements, but without them
+ * the value of num_after is only reduced by
+ * the number of mask bits per pass. There are
+ * cases where num_after can be close to 2^64.
+ * Without this code it could take nearly
+ * (2^64) / 32 passes to perform the full
+ * reduction.
+ */
+ if (num_contiguous == MASK_BITS) {
+ prev->num_after += nodep->num_after;
+ nodep->num_after = 0;
+ }
+
+ reduction_performed = true;
+ continue;
+ }
+ }
+
+ /*
+ * 3) Potential reductions between the current and
+ * next nodes.
+ */
+ next = node_next(s, nodep);
+ if (next) {
+ /* Nodes with no bits set can be removed. */
+ if (next->mask == 0 && next->num_after == 0) {
+ node_rm(s, next);
+ reduction_performed = true;
+ continue;
+ }
+
+ /*
+ * Is next node index adjacent to current node
+ * and has a mask with all bits set?
+ */
+ if (next->idx == nodep->idx + MASK_BITS + nodep->num_after &&
+ next->mask == ~(mask_t) 0) {
+ nodep->num_after += MASK_BITS;
+ next->mask = 0;
+ nodep->num_after += next->num_after;
+ next->num_after = 0;
+
+ node_rm(s, next);
+ next = NULL;
+
+ reduction_performed = true;
+ continue;
+ }
+ }
+ } while (nodep && reduction_performed);
+}
+
+/* Returns whether the bit at the index given by idx, within the
+ * sparsebit array is set or not.
+ */
+bool sparsebit_is_set(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep;
+
+ /* Find the node that describes the setting of the bit at idx */
+ for (nodep = s->root; nodep;
+ nodep = nodep->idx > idx ? nodep->left : nodep->right)
+ if (idx >= nodep->idx &&
+ idx <= nodep->idx + MASK_BITS + nodep->num_after - 1)
+ goto have_node;
+
+ return false;
+
+have_node:
+ /* Bit is set if it is any of the bits described by num_after */
+ if (nodep->num_after && idx >= nodep->idx + MASK_BITS)
+ return true;
+
+ /* Is the corresponding mask bit set */
+ assert(idx >= nodep->idx && idx - nodep->idx < MASK_BITS);
+ return !!(nodep->mask & (1 << (idx - nodep->idx)));
+}
+
+/* Within the sparsebit array pointed to by s, sets the bit
+ * at the index given by idx.
+ */
+static void bit_set(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep;
+
+ /* Skip bits that are already set */
+ if (sparsebit_is_set(s, idx))
+ return;
+
+ /*
+ * Get a node where the bit at idx is described by the mask.
+ * The node_split will also create a node, if there isn't
+ * already a node that describes the setting of bit.
+ */
+ nodep = node_split(s, idx & -MASK_BITS);
+
+ /* Set the bit within the nodes mask */
+ assert(idx >= nodep->idx && idx <= nodep->idx + MASK_BITS - 1);
+ assert(!(nodep->mask & (1 << (idx - nodep->idx))));
+ nodep->mask |= 1 << (idx - nodep->idx);
+ s->num_set++;
+
+ node_reduce(s, nodep);
+}
+
+/* Within the sparsebit array pointed to by s, clears the bit
+ * at the index given by idx.
+ */
+static void bit_clear(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ struct node *nodep;
+
+ /* Skip bits that are already cleared */
+ if (!sparsebit_is_set(s, idx))
+ return;
+
+ /* Is there a node that describes the setting of this bit? */
+ nodep = node_find(s, idx);
+ if (!nodep)
+ return;
+
+ /*
+ * If a num_after bit, split the node, so that the bit is
+ * part of a node mask.
+ */
+ if (idx >= nodep->idx + MASK_BITS)
+ nodep = node_split(s, idx & -MASK_BITS);
+
+ /*
+ * After node_split above, bit at idx should be within the mask.
+ * Clear that bit.
+ */
+ assert(idx >= nodep->idx && idx <= nodep->idx + MASK_BITS - 1);
+ assert(nodep->mask & (1 << (idx - nodep->idx)));
+ nodep->mask &= ~(1 << (idx - nodep->idx));
+ assert(s->num_set > 0 || sparsebit_all_set(s));
+ s->num_set--;
+
+ node_reduce(s, nodep);
+}
+
+/* Recursively dumps to the FILE stream given by stream the contents
+ * of the sub-tree of nodes pointed to by nodep. Each line of output
+ * is prefixed by the number of spaces given by indent. On each
+ * recursion, the indent amount is increased by 2. This causes nodes
+ * at each level deeper into the binary search tree to be displayed
+ * with a greater indent.
+ */
+static void dump_nodes(FILE *stream, struct node *nodep,
+ unsigned int indent)
+{
+ char *node_type;
+
+ /* Dump contents of node */
+ if (!nodep->parent)
+ node_type = "root";
+ else if (nodep == nodep->parent->left)
+ node_type = "left";
+ else {
+ assert(nodep == nodep->parent->right);
+ node_type = "right";
+ }
+ fprintf(stream, "%*s---- %s nodep: %p\n", indent, "", node_type, nodep);
+ fprintf(stream, "%*s parent: %p left: %p right: %p\n", indent, "",
+ nodep->parent, nodep->left, nodep->right);
+ fprintf(stream, "%*s idx: 0x%lx mask: 0x%x num_after: 0x%lx\n",
+ indent, "", nodep->idx, nodep->mask, nodep->num_after);
+
+ /* If present, dump contents of left child nodes */
+ if (nodep->left)
+ dump_nodes(stream, nodep->left, indent + 2);
+
+ /* If present, dump contents of right child nodes */
+ if (nodep->right)
+ dump_nodes(stream, nodep->right, indent + 2);
+}
+
+static inline sparsebit_idx_t node_first_set(struct node *nodep, int start)
+{
+ mask_t leading = (mask_t)1 << start;
+ int n1 = __builtin_ctz(nodep->mask & -leading);
+
+ return nodep->idx + n1;
+}
+
+static inline sparsebit_idx_t node_first_clear(struct node *nodep, int start)
+{
+ mask_t leading = (mask_t)1 << start;
+ int n1 = __builtin_ctz(~nodep->mask & -leading);
+
+ return nodep->idx + n1;
+}
+
+/* Dumps to the FILE stream specified by stream, the implementation dependent
+ * internal state of s. Each line of output is prefixed with the number
+ * of spaces given by indent. The output is completely implementation
+ * dependent and subject to change. Output from this function should only
+ * be used for diagnostic purposes. For example, this function can be
+ * used by test cases after they detect an unexpected condition, as a means
+ * to capture diagnostic information.
+ */
+static void sparsebit_dump_internal(FILE *stream, struct sparsebit *s,
+ unsigned int indent)
+{
+ /* Dump the contents of s */
+ fprintf(stream, "%*sroot: %p\n", indent, "", s->root);
+ fprintf(stream, "%*snum_set: 0x%lx\n", indent, "", s->num_set);
+
+ if (s->root)
+ dump_nodes(stream, s->root, indent);
+}
+
+/* Allocates and returns a new sparsebit array. The initial state
+ * of the newly allocated sparsebit array has all bits cleared.
+ */
+struct sparsebit *sparsebit_alloc(void)
+{
+ struct sparsebit *s;
+
+ /* Allocate top level structure. */
+ s = calloc(1, sizeof(*s));
+ if (!s) {
+ perror("calloc");
+ abort();
+ }
+
+ return s;
+}
+
+/* Frees the implementation dependent data for the sparsebit array
+ * pointed to by s and poisons the pointer to that data.
+ */
+void sparsebit_free(struct sparsebit **sbitp)
+{
+ struct sparsebit *s = *sbitp;
+
+ if (!s)
+ return;
+
+ sparsebit_clear_all(s);
+ free(s);
+ *sbitp = NULL;
+}
+
+/* Makes a copy of the sparsebit array given by s, to the sparsebit
+ * array given by d. Note, d must have already been allocated via
+ * sparsebit_alloc(). It can though already have bits set, which
+ * if different from src will be cleared.
+ */
+void sparsebit_copy(struct sparsebit *d, struct sparsebit *s)
+{
+ /* First clear any bits already set in the destination */
+ sparsebit_clear_all(d);
+
+ if (s->root) {
+ d->root = node_copy_subtree(s->root);
+ d->num_set = s->num_set;
+ }
+}
+
+/* Returns whether num consecutive bits starting at idx are all set. */
+bool sparsebit_is_set_num(struct sparsebit *s,
+ sparsebit_idx_t idx, sparsebit_num_t num)
+{
+ sparsebit_idx_t next_cleared;
+
+ assert(num > 0);
+ assert(idx + num - 1 >= idx);
+
+ /* With num > 0, the first bit must be set. */
+ if (!sparsebit_is_set(s, idx))
+ return false;
+
+ /* Find the next cleared bit */
+ next_cleared = sparsebit_next_clear(s, idx);
+
+ /*
+ * If no cleared bits beyond idx, then there are at least num
+ * set bits. idx + num doesn't wrap. Otherwise check if
+ * there are enough set bits between idx and the next cleared bit.
+ */
+ return next_cleared == 0 || next_cleared - idx >= num;
+}
+
+/* Returns whether the bit at the index given by idx. */
+bool sparsebit_is_clear(struct sparsebit *s,
+ sparsebit_idx_t idx)
+{
+ return !sparsebit_is_set(s, idx);
+}
+
+/* Returns whether num consecutive bits starting at idx are all cleared. */
+bool sparsebit_is_clear_num(struct sparsebit *s,
+ sparsebit_idx_t idx, sparsebit_num_t num)
+{
+ sparsebit_idx_t next_set;
+
+ assert(num > 0);
+ assert(idx + num - 1 >= idx);
+
+ /* With num > 0, the first bit must be cleared. */
+ if (!sparsebit_is_clear(s, idx))
+ return false;
+
+ /* Find the next set bit */
+ next_set = sparsebit_next_set(s, idx);
+
+ /*
+ * If no set bits beyond idx, then there are at least num
+ * cleared bits. idx + num doesn't wrap. Otherwise check if
+ * there are enough cleared bits between idx and the next set bit.
+ */
+ return next_set == 0 || next_set - idx >= num;
+}
+
+/* Returns the total number of bits set. Note: 0 is also returned for
+ * the case of all bits set. This is because with all bits set, there
+ * is 1 additional bit set beyond what can be represented in the return
+ * value. Use sparsebit_any_set(), instead of sparsebit_num_set() > 0,
+ * to determine if the sparsebit array has any bits set.
+ */
+sparsebit_num_t sparsebit_num_set(struct sparsebit *s)
+{
+ return s->num_set;
+}
+
+/* Returns whether any bit is set in the sparsebit array. */
+bool sparsebit_any_set(struct sparsebit *s)
+{
+ /*
+ * Nodes only describe set bits. If any nodes then there
+ * is at least 1 bit set.
+ */
+ if (!s->root)
+ return false;
+
+ /*
+ * Every node should have a non-zero mask. For now will
+ * just assure that the root node has a non-zero mask,
+ * which is a quick check that at least 1 bit is set.
+ */
+ assert(s->root->mask != 0);
+ assert(s->num_set > 0 ||
+ (s->root->num_after == ((sparsebit_num_t) 0) - MASK_BITS &&
+ s->root->mask == ~(mask_t) 0));
+
+ return true;
+}
+
+/* Returns whether all the bits in the sparsebit array are cleared. */
+bool sparsebit_all_clear(struct sparsebit *s)
+{
+ return !sparsebit_any_set(s);
+}
+
+/* Returns whether all the bits in the sparsebit array are set. */
+bool sparsebit_any_clear(struct sparsebit *s)
+{
+ return !sparsebit_all_set(s);
+}
+
+/* Returns the index of the first set bit. Abort if no bits are set.
+ */
+sparsebit_idx_t sparsebit_first_set(struct sparsebit *s)
+{
+ struct node *nodep;
+
+ /* Validate at least 1 bit is set */
+ assert(sparsebit_any_set(s));
+
+ nodep = node_first(s);
+ return node_first_set(nodep, 0);
+}
+
+/* Returns the index of the first cleared bit. Abort if
+ * no bits are cleared.
+ */
+sparsebit_idx_t sparsebit_first_clear(struct sparsebit *s)
+{
+ struct node *nodep1, *nodep2;
+
+ /* Validate at least 1 bit is cleared. */
+ assert(sparsebit_any_clear(s));
+
+ /* If no nodes or first node index > 0 then lowest cleared is 0 */
+ nodep1 = node_first(s);
+ if (!nodep1 || nodep1->idx > 0)
+ return 0;
+
+ /* Does the mask in the first node contain any cleared bits. */
+ if (nodep1->mask != ~(mask_t) 0)
+ return node_first_clear(nodep1, 0);
+
+ /*
+ * All mask bits set in first node. If there isn't a second node
+ * then the first cleared bit is the first bit after the bits
+ * described by the first node.
+ */
+ nodep2 = node_next(s, nodep1);
+ if (!nodep2) {
+ /*
+ * No second node. First cleared bit is first bit beyond
+ * bits described by first node.
+ */
+ assert(nodep1->mask == ~(mask_t) 0);
+ assert(nodep1->idx + MASK_BITS + nodep1->num_after != (sparsebit_idx_t) 0);
+ return nodep1->idx + MASK_BITS + nodep1->num_after;
+ }
+
+ /*
+ * There is a second node.
+ * If it is not adjacent to the first node, then there is a gap
+ * of cleared bits between the nodes, and the first cleared bit
+ * is the first bit within the gap.
+ */
+ if (nodep1->idx + MASK_BITS + nodep1->num_after != nodep2->idx)
+ return nodep1->idx + MASK_BITS + nodep1->num_after;
+
+ /*
+ * Second node is adjacent to the first node.
+ * Because it is adjacent, its mask should be non-zero. If all
+ * its mask bits are set, then with it being adjacent, it should
+ * have had the mask bits moved into the num_after setting of the
+ * previous node.
+ */
+ return node_first_clear(nodep2, 0);
+}
+
+/* Returns index of next bit set within s after the index given by prev.
+ * Returns 0 if there are no bits after prev that are set.
+ */
+sparsebit_idx_t sparsebit_next_set(struct sparsebit *s,
+ sparsebit_idx_t prev)
+{
+ sparsebit_idx_t lowest_possible = prev + 1;
+ sparsebit_idx_t start;
+ struct node *nodep;
+
+ /* A bit after the highest index can't be set. */
+ if (lowest_possible == 0)
+ return 0;
+
+ /*
+ * Find the leftmost 'candidate' overlapping or to the right
+ * of lowest_possible.
+ */
+ struct node *candidate = NULL;
+
+ /* True iff lowest_possible is within candidate */
+ bool contains = false;
+
+ /*
+ * Find node that describes setting of bit at lowest_possible.
+ * If such a node doesn't exist, find the node with the lowest
+ * starting index that is > lowest_possible.
+ */
+ for (nodep = s->root; nodep;) {
+ if ((nodep->idx + MASK_BITS + nodep->num_after - 1)
+ >= lowest_possible) {
+ candidate = nodep;
+ if (candidate->idx <= lowest_possible) {
+ contains = true;
+ break;
+ }
+ nodep = nodep->left;
+ } else {
+ nodep = nodep->right;
+ }
+ }
+ if (!candidate)
+ return 0;
+
+ assert(candidate->mask != 0);
+
+ /* Does the candidate node describe the setting of lowest_possible? */
+ if (!contains) {
+ /*
+ * Candidate doesn't describe setting of bit at lowest_possible.
+ * Candidate points to the first node with a starting index
+ * > lowest_possible.
+ */
+ assert(candidate->idx > lowest_possible);
+
+ return node_first_set(candidate, 0);
+ }
+
+ /*
+ * Candidate describes setting of bit at lowest_possible.
+ * Note: although the node describes the setting of the bit
+ * at lowest_possible, its possible that its setting and the
+ * setting of all latter bits described by this node are 0.
+ * For now, just handle the cases where this node describes
+ * a bit at or after an index of lowest_possible that is set.
+ */
+ start = lowest_possible - candidate->idx;
+
+ if (start < MASK_BITS && candidate->mask >= (1 << start))
+ return node_first_set(candidate, start);
+
+ if (candidate->num_after) {
+ sparsebit_idx_t first_num_after_idx = candidate->idx + MASK_BITS;
+
+ return lowest_possible < first_num_after_idx
+ ? first_num_after_idx : lowest_possible;
+ }
+
+ /*
+ * Although candidate node describes setting of bit at
+ * the index of lowest_possible, all bits at that index and
+ * latter that are described by candidate are cleared. With
+ * this, the next bit is the first bit in the next node, if
+ * such a node exists. If a next node doesn't exist, then
+ * there is no next set bit.
+ */
+ candidate = node_next(s, candidate);
+ if (!candidate)
+ return 0;
+
+ return node_first_set(candidate, 0);
+}
+
+/* Returns index of next bit cleared within s after the index given by prev.
+ * Returns 0 if there are no bits after prev that are cleared.
+ */
+sparsebit_idx_t sparsebit_next_clear(struct sparsebit *s,
+ sparsebit_idx_t prev)
+{
+ sparsebit_idx_t lowest_possible = prev + 1;
+ sparsebit_idx_t idx;
+ struct node *nodep1, *nodep2;
+
+ /* A bit after the highest index can't be set. */
+ if (lowest_possible == 0)
+ return 0;
+
+ /*
+ * Does a node describing the setting of lowest_possible exist?
+ * If not, the bit at lowest_possible is cleared.
+ */
+ nodep1 = node_find(s, lowest_possible);
+ if (!nodep1)
+ return lowest_possible;
+
+ /* Does a mask bit in node 1 describe the next cleared bit. */
+ for (idx = lowest_possible - nodep1->idx; idx < MASK_BITS; idx++)
+ if (!(nodep1->mask & (1 << idx)))
+ return nodep1->idx + idx;
+
+ /*
+ * Next cleared bit is not described by node 1. If there
+ * isn't a next node, then next cleared bit is described
+ * by bit after the bits described by the first node.
+ */
+ nodep2 = node_next(s, nodep1);
+ if (!nodep2)
+ return nodep1->idx + MASK_BITS + nodep1->num_after;
+
+ /*
+ * There is a second node.
+ * If it is not adjacent to the first node, then there is a gap
+ * of cleared bits between the nodes, and the next cleared bit
+ * is the first bit within the gap.
+ */
+ if (nodep1->idx + MASK_BITS + nodep1->num_after != nodep2->idx)
+ return nodep1->idx + MASK_BITS + nodep1->num_after;
+
+ /*
+ * Second node is adjacent to the first node.
+ * Because it is adjacent, its mask should be non-zero. If all
+ * its mask bits are set, then with it being adjacent, it should
+ * have had the mask bits moved into the num_after setting of the
+ * previous node.
+ */
+ return node_first_clear(nodep2, 0);
+}
+
+/* Starting with the index 1 greater than the index given by start, finds
+ * and returns the index of the first sequence of num consecutively set
+ * bits. Returns a value of 0 of no such sequence exists.
+ */
+sparsebit_idx_t sparsebit_next_set_num(struct sparsebit *s,
+ sparsebit_idx_t start, sparsebit_num_t num)
+{
+ sparsebit_idx_t idx;
+
+ assert(num >= 1);
+
+ for (idx = sparsebit_next_set(s, start);
+ idx != 0 && idx + num - 1 >= idx;
+ idx = sparsebit_next_set(s, idx)) {
+ assert(sparsebit_is_set(s, idx));
+
+ /*
+ * Does the sequence of bits starting at idx consist of
+ * num set bits?
+ */
+ if (sparsebit_is_set_num(s, idx, num))
+ return idx;
+
+ /*
+ * Sequence of set bits at idx isn't large enough.
+ * Skip this entire sequence of set bits.
+ */
+ idx = sparsebit_next_clear(s, idx);
+ if (idx == 0)
+ return 0;
+ }
+
+ return 0;
+}
+
+/* Starting with the index 1 greater than the index given by start, finds
+ * and returns the index of the first sequence of num consecutively cleared
+ * bits. Returns a value of 0 of no such sequence exists.
+ */
+sparsebit_idx_t sparsebit_next_clear_num(struct sparsebit *s,
+ sparsebit_idx_t start, sparsebit_num_t num)
+{
+ sparsebit_idx_t idx;
+
+ assert(num >= 1);
+
+ for (idx = sparsebit_next_clear(s, start);
+ idx != 0 && idx + num - 1 >= idx;
+ idx = sparsebit_next_clear(s, idx)) {
+ assert(sparsebit_is_clear(s, idx));
+
+ /*
+ * Does the sequence of bits starting at idx consist of
+ * num cleared bits?
+ */
+ if (sparsebit_is_clear_num(s, idx, num))
+ return idx;
+
+ /*
+ * Sequence of cleared bits at idx isn't large enough.
+ * Skip this entire sequence of cleared bits.
+ */
+ idx = sparsebit_next_set(s, idx);
+ if (idx == 0)
+ return 0;
+ }
+
+ return 0;
+}
+
+/* Sets the bits * in the inclusive range idx through idx + num - 1. */
+void sparsebit_set_num(struct sparsebit *s,
+ sparsebit_idx_t start, sparsebit_num_t num)
+{
+ struct node *nodep, *next;
+ unsigned int n1;
+ sparsebit_idx_t idx;
+ sparsebit_num_t n;
+ sparsebit_idx_t middle_start, middle_end;
+
+ assert(num > 0);
+ assert(start + num - 1 >= start);
+
+ /*
+ * Leading - bits before first mask boundary.
+ *
+ * TODO(lhuemill): With some effort it may be possible to
+ * replace the following loop with a sequential sequence
+ * of statements. High level sequence would be:
+ *
+ * 1. Use node_split() to force node that describes setting
+ * of idx to be within the mask portion of a node.
+ * 2. Form mask of bits to be set.
+ * 3. Determine number of mask bits already set in the node
+ * and store in a local variable named num_already_set.
+ * 4. Set the appropriate mask bits within the node.
+ * 5. Increment struct sparsebit_pvt num_set member
+ * by the number of bits that were actually set.
+ * Exclude from the counts bits that were already set.
+ * 6. Before returning to the caller, use node_reduce() to
+ * handle the multiple corner cases that this method
+ * introduces.
+ */
+ for (idx = start, n = num; n > 0 && idx % MASK_BITS != 0; idx++, n--)
+ bit_set(s, idx);
+
+ /* Middle - bits spanning one or more entire mask */
+ middle_start = idx;
+ middle_end = middle_start + (n & -MASK_BITS) - 1;
+ if (n >= MASK_BITS) {
+ nodep = node_split(s, middle_start);
+
+ /*
+ * As needed, split just after end of middle bits.
+ * No split needed if end of middle bits is at highest
+ * supported bit index.
+ */
+ if (middle_end + 1 > middle_end)
+ (void) node_split(s, middle_end + 1);
+
+ /* Delete nodes that only describe bits within the middle. */
+ for (next = node_next(s, nodep);
+ next && (next->idx < middle_end);
+ next = node_next(s, nodep)) {
+ assert(next->idx + MASK_BITS + next->num_after - 1 <= middle_end);
+ node_rm(s, next);
+ next = NULL;
+ }
+
+ /* As needed set each of the mask bits */
+ for (n1 = 0; n1 < MASK_BITS; n1++) {
+ if (!(nodep->mask & (1 << n1))) {
+ nodep->mask |= 1 << n1;
+ s->num_set++;
+ }
+ }
+
+ s->num_set -= nodep->num_after;
+ nodep->num_after = middle_end - middle_start + 1 - MASK_BITS;
+ s->num_set += nodep->num_after;
+
+ node_reduce(s, nodep);
+ }
+ idx = middle_end + 1;
+ n -= middle_end - middle_start + 1;
+
+ /* Trailing - bits at and beyond last mask boundary */
+ assert(n < MASK_BITS);
+ for (; n > 0; idx++, n--)
+ bit_set(s, idx);
+}
+
+/* Clears the bits * in the inclusive range idx through idx + num - 1. */
+void sparsebit_clear_num(struct sparsebit *s,
+ sparsebit_idx_t start, sparsebit_num_t num)
+{
+ struct node *nodep, *next;
+ unsigned int n1;
+ sparsebit_idx_t idx;
+ sparsebit_num_t n;
+ sparsebit_idx_t middle_start, middle_end;
+
+ assert(num > 0);
+ assert(start + num - 1 >= start);
+
+ /* Leading - bits before first mask boundary */
+ for (idx = start, n = num; n > 0 && idx % MASK_BITS != 0; idx++, n--)
+ bit_clear(s, idx);
+
+ /* Middle - bits spanning one or more entire mask */
+ middle_start = idx;
+ middle_end = middle_start + (n & -MASK_BITS) - 1;
+ if (n >= MASK_BITS) {
+ nodep = node_split(s, middle_start);
+
+ /*
+ * As needed, split just after end of middle bits.
+ * No split needed if end of middle bits is at highest
+ * supported bit index.
+ */
+ if (middle_end + 1 > middle_end)
+ (void) node_split(s, middle_end + 1);
+
+ /* Delete nodes that only describe bits within the middle. */
+ for (next = node_next(s, nodep);
+ next && (next->idx < middle_end);
+ next = node_next(s, nodep)) {
+ assert(next->idx + MASK_BITS + next->num_after - 1 <= middle_end);
+ node_rm(s, next);
+ next = NULL;
+ }
+
+ /* As needed clear each of the mask bits */
+ for (n1 = 0; n1 < MASK_BITS; n1++) {
+ if (nodep->mask & (1 << n1)) {
+ nodep->mask &= ~(1 << n1);
+ s->num_set--;
+ }
+ }
+
+ /* Clear any bits described by num_after */
+ s->num_set -= nodep->num_after;
+ nodep->num_after = 0;
+
+ /*
+ * Delete the node that describes the beginning of
+ * the middle bits and perform any allowed reductions
+ * with the nodes prev or next of nodep.
+ */
+ node_reduce(s, nodep);
+ nodep = NULL;
+ }
+ idx = middle_end + 1;
+ n -= middle_end - middle_start + 1;
+
+ /* Trailing - bits at and beyond last mask boundary */
+ assert(n < MASK_BITS);
+ for (; n > 0; idx++, n--)
+ bit_clear(s, idx);
+}
+
+/* Sets the bit at the index given by idx. */
+void sparsebit_set(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ sparsebit_set_num(s, idx, 1);
+}
+
+/* Clears the bit at the index given by idx. */
+void sparsebit_clear(struct sparsebit *s, sparsebit_idx_t idx)
+{
+ sparsebit_clear_num(s, idx, 1);
+}
+
+/* Sets the bits in the entire addressable range of the sparsebit array. */
+void sparsebit_set_all(struct sparsebit *s)
+{
+ sparsebit_set(s, 0);
+ sparsebit_set_num(s, 1, ~(sparsebit_idx_t) 0);
+ assert(sparsebit_all_set(s));
+}
+
+/* Clears the bits in the entire addressable range of the sparsebit array. */
+void sparsebit_clear_all(struct sparsebit *s)
+{
+ sparsebit_clear(s, 0);
+ sparsebit_clear_num(s, 1, ~(sparsebit_idx_t) 0);
+ assert(!sparsebit_any_set(s));
+}
+
+static size_t display_range(FILE *stream, sparsebit_idx_t low,
+ sparsebit_idx_t high, bool prepend_comma_space)
+{
+ char *fmt_str;
+ size_t sz;
+
+ /* Determine the printf format string */
+ if (low == high)
+ fmt_str = prepend_comma_space ? ", 0x%lx" : "0x%lx";
+ else
+ fmt_str = prepend_comma_space ? ", 0x%lx:0x%lx" : "0x%lx:0x%lx";
+
+ /*
+ * When stream is NULL, just determine the size of what would
+ * have been printed, else print the range.
+ */
+ if (!stream)
+ sz = snprintf(NULL, 0, fmt_str, low, high);
+ else
+ sz = fprintf(stream, fmt_str, low, high);
+
+ return sz;
+}
+
+
+/* Dumps to the FILE stream given by stream, the bit settings
+ * of s. Each line of output is prefixed with the number of
+ * spaces given by indent. The length of each line is implementation
+ * dependent and does not depend on the indent amount. The following
+ * is an example output of a sparsebit array that has bits:
+ *
+ * 0x5, 0x8, 0xa:0xe, 0x12
+ *
+ * This corresponds to a sparsebit whose bits 5, 8, 10, 11, 12, 13, 14, 18
+ * are set. Note that a ':', instead of a '-' is used to specify a range of
+ * contiguous bits. This is done because '-' is used to specify command-line
+ * options, and sometimes ranges are specified as command-line arguments.
+ */
+void sparsebit_dump(FILE *stream, struct sparsebit *s,
+ unsigned int indent)
+{
+ size_t current_line_len = 0;
+ size_t sz;
+ struct node *nodep;
+
+ if (!sparsebit_any_set(s))
+ return;
+
+ /* Display initial indent */
+ fprintf(stream, "%*s", indent, "");
+
+ /* For each node */
+ for (nodep = node_first(s); nodep; nodep = node_next(s, nodep)) {
+ unsigned int n1;
+ sparsebit_idx_t low, high;
+
+ /* For each group of bits in the mask */
+ for (n1 = 0; n1 < MASK_BITS; n1++) {
+ if (nodep->mask & (1 << n1)) {
+ low = high = nodep->idx + n1;
+
+ for (; n1 < MASK_BITS; n1++) {
+ if (nodep->mask & (1 << n1))
+ high = nodep->idx + n1;
+ else
+ break;
+ }
+
+ if ((n1 == MASK_BITS) && nodep->num_after)
+ high += nodep->num_after;
+
+ /*
+ * How much room will it take to display
+ * this range.
+ */
+ sz = display_range(NULL, low, high,
+ current_line_len != 0);
+
+ /*
+ * If there is not enough room, display
+ * a newline plus the indent of the next
+ * line.
+ */
+ if (current_line_len + sz > DUMP_LINE_MAX) {
+ fputs("\n", stream);
+ fprintf(stream, "%*s", indent, "");
+ current_line_len = 0;
+ }
+
+ /* Display the range */
+ sz = display_range(stream, low, high,
+ current_line_len != 0);
+ current_line_len += sz;
+ }
+ }
+
+ /*
+ * If num_after and most significant-bit of mask is not
+ * set, then still need to display a range for the bits
+ * described by num_after.
+ */
+ if (!(nodep->mask & (1 << (MASK_BITS - 1))) && nodep->num_after) {
+ low = nodep->idx + MASK_BITS;
+ high = nodep->idx + MASK_BITS + nodep->num_after - 1;
+
+ /*
+ * How much room will it take to display
+ * this range.
+ */
+ sz = display_range(NULL, low, high,
+ current_line_len != 0);
+
+ /*
+ * If there is not enough room, display
+ * a newline plus the indent of the next
+ * line.
+ */
+ if (current_line_len + sz > DUMP_LINE_MAX) {
+ fputs("\n", stream);
+ fprintf(stream, "%*s", indent, "");
+ current_line_len = 0;
+ }
+
+ /* Display the range */
+ sz = display_range(stream, low, high,
+ current_line_len != 0);
+ current_line_len += sz;
+ }
+ }
+ fputs("\n", stream);
+}
+
+/* Validates the internal state of the sparsebit array given by
+ * s. On error, diagnostic information is printed to stderr and
+ * abort is called.
+ */
+void sparsebit_validate_internal(struct sparsebit *s)
+{
+ bool error_detected = false;
+ struct node *nodep, *prev = NULL;
+ sparsebit_num_t total_bits_set = 0;
+ unsigned int n1;
+
+ /* For each node */
+ for (nodep = node_first(s); nodep;
+ prev = nodep, nodep = node_next(s, nodep)) {
+
+ /*
+ * Increase total bits set by the number of bits set
+ * in this node.
+ */
+ for (n1 = 0; n1 < MASK_BITS; n1++)
+ if (nodep->mask & (1 << n1))
+ total_bits_set++;
+
+ total_bits_set += nodep->num_after;
+
+ /*
+ * Arbitrary choice as to whether a mask of 0 is allowed
+ * or not. For diagnostic purposes it is beneficial to
+ * have only one valid means to represent a set of bits.
+ * To support this an arbitrary choice has been made
+ * to not allow a mask of zero.
+ */
+ if (nodep->mask == 0) {
+ fprintf(stderr, "Node mask of zero, "
+ "nodep: %p nodep->mask: 0x%x",
+ nodep, nodep->mask);
+ error_detected = true;
+ break;
+ }
+
+ /*
+ * Validate num_after is not greater than the max index
+ * - the number of mask bits. The num_after member
+ * uses 0-based indexing and thus has no value that
+ * represents all bits set. This limitation is handled
+ * by requiring a non-zero mask. With a non-zero mask,
+ * MASK_BITS worth of bits are described by the mask,
+ * which makes the largest needed num_after equal to:
+ *
+ * (~(sparsebit_num_t) 0) - MASK_BITS + 1
+ */
+ if (nodep->num_after
+ > (~(sparsebit_num_t) 0) - MASK_BITS + 1) {
+ fprintf(stderr, "num_after too large, "
+ "nodep: %p nodep->num_after: 0x%lx",
+ nodep, nodep->num_after);
+ error_detected = true;
+ break;
+ }
+
+ /* Validate node index is divisible by the mask size */
+ if (nodep->idx % MASK_BITS) {
+ fprintf(stderr, "Node index not divisible by "
+ "mask size,\n"
+ " nodep: %p nodep->idx: 0x%lx "
+ "MASK_BITS: %lu\n",
+ nodep, nodep->idx, MASK_BITS);
+ error_detected = true;
+ break;
+ }
+
+ /*
+ * Validate bits described by node don't wrap beyond the
+ * highest supported index.
+ */
+ if ((nodep->idx + MASK_BITS + nodep->num_after - 1) < nodep->idx) {
+ fprintf(stderr, "Bits described by node wrap "
+ "beyond highest supported index,\n"
+ " nodep: %p nodep->idx: 0x%lx\n"
+ " MASK_BITS: %lu nodep->num_after: 0x%lx",
+ nodep, nodep->idx, MASK_BITS, nodep->num_after);
+ error_detected = true;
+ break;
+ }
+
+ /* Check parent pointers. */
+ if (nodep->left) {
+ if (nodep->left->parent != nodep) {
+ fprintf(stderr, "Left child parent pointer "
+ "doesn't point to this node,\n"
+ " nodep: %p nodep->left: %p "
+ "nodep->left->parent: %p",
+ nodep, nodep->left,
+ nodep->left->parent);
+ error_detected = true;
+ break;
+ }
+ }
+
+ if (nodep->right) {
+ if (nodep->right->parent != nodep) {
+ fprintf(stderr, "Right child parent pointer "
+ "doesn't point to this node,\n"
+ " nodep: %p nodep->right: %p "
+ "nodep->right->parent: %p",
+ nodep, nodep->right,
+ nodep->right->parent);
+ error_detected = true;
+ break;
+ }
+ }
+
+ if (!nodep->parent) {
+ if (s->root != nodep) {
+ fprintf(stderr, "Unexpected root node, "
+ "s->root: %p nodep: %p",
+ s->root, nodep);
+ error_detected = true;
+ break;
+ }
+ }
+
+ if (prev) {
+ /*
+ * Is index of previous node before index of
+ * current node?
+ */
+ if (prev->idx >= nodep->idx) {
+ fprintf(stderr, "Previous node index "
+ ">= current node index,\n"
+ " prev: %p prev->idx: 0x%lx\n"
+ " nodep: %p nodep->idx: 0x%lx",
+ prev, prev->idx, nodep, nodep->idx);
+ error_detected = true;
+ break;
+ }
+
+ /*
+ * Nodes occur in asscending order, based on each
+ * nodes starting index.
+ */
+ if ((prev->idx + MASK_BITS + prev->num_after - 1)
+ >= nodep->idx) {
+ fprintf(stderr, "Previous node bit range "
+ "overlap with current node bit range,\n"
+ " prev: %p prev->idx: 0x%lx "
+ "prev->num_after: 0x%lx\n"
+ " nodep: %p nodep->idx: 0x%lx "
+ "nodep->num_after: 0x%lx\n"
+ " MASK_BITS: %lu",
+ prev, prev->idx, prev->num_after,
+ nodep, nodep->idx, nodep->num_after,
+ MASK_BITS);
+ error_detected = true;
+ break;
+ }
+
+ /*
+ * When the node has all mask bits set, it shouldn't
+ * be adjacent to the last bit described by the
+ * previous node.
+ */
+ if (nodep->mask == ~(mask_t) 0 &&
+ prev->idx + MASK_BITS + prev->num_after == nodep->idx) {
+ fprintf(stderr, "Current node has mask with "
+ "all bits set and is adjacent to the "
+ "previous node,\n"
+ " prev: %p prev->idx: 0x%lx "
+ "prev->num_after: 0x%lx\n"
+ " nodep: %p nodep->idx: 0x%lx "
+ "nodep->num_after: 0x%lx\n"
+ " MASK_BITS: %lu",
+ prev, prev->idx, prev->num_after,
+ nodep, nodep->idx, nodep->num_after,
+ MASK_BITS);
+
+ error_detected = true;
+ break;
+ }
+ }
+ }
+
+ if (!error_detected) {
+ /*
+ * Is sum of bits set in each node equal to the count
+ * of total bits set.
+ */
+ if (s->num_set != total_bits_set) {
+ fprintf(stderr, "Number of bits set missmatch,\n"
+ " s->num_set: 0x%lx total_bits_set: 0x%lx",
+ s->num_set, total_bits_set);
+
+ error_detected = true;
+ }
+ }
+
+ if (error_detected) {
+ fputs(" dump_internal:\n", stderr);
+ sparsebit_dump_internal(stderr, s, 4);
+ abort();
+ }
+}
+
+
+#ifdef FUZZ
+/* A simple but effective fuzzing driver. Look for bugs with the help
+ * of some invariants and of a trivial representation of sparsebit.
+ * Just use 512 bytes of /dev/zero and /dev/urandom as inputs, and let
+ * afl-fuzz do the magic. :)
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+struct range {
+ sparsebit_idx_t first, last;
+ bool set;
+};
+
+struct sparsebit *s;
+struct range ranges[1000];
+int num_ranges;
+
+static bool get_value(sparsebit_idx_t idx)
+{
+ int i;
+
+ for (i = num_ranges; --i >= 0; )
+ if (ranges[i].first <= idx && idx <= ranges[i].last)
+ return ranges[i].set;
+
+ return false;
+}
+
+static void operate(int code, sparsebit_idx_t first, sparsebit_idx_t last)
+{
+ sparsebit_num_t num;
+ sparsebit_idx_t next;
+
+ if (first < last) {
+ num = last - first + 1;
+ } else {
+ num = first - last + 1;
+ first = last;
+ last = first + num - 1;
+ }
+
+ switch (code) {
+ case 0:
+ sparsebit_set(s, first);
+ assert(sparsebit_is_set(s, first));
+ assert(!sparsebit_is_clear(s, first));
+ assert(sparsebit_any_set(s));
+ assert(!sparsebit_all_clear(s));
+ if (get_value(first))
+ return;
+ if (num_ranges == 1000)
+ exit(0);
+ ranges[num_ranges++] = (struct range)
+ { .first = first, .last = first, .set = true };
+ break;
+ case 1:
+ sparsebit_clear(s, first);
+ assert(!sparsebit_is_set(s, first));
+ assert(sparsebit_is_clear(s, first));
+ assert(sparsebit_any_clear(s));
+ assert(!sparsebit_all_set(s));
+ if (!get_value(first))
+ return;
+ if (num_ranges == 1000)
+ exit(0);
+ ranges[num_ranges++] = (struct range)
+ { .first = first, .last = first, .set = false };
+ break;
+ case 2:
+ assert(sparsebit_is_set(s, first) == get_value(first));
+ assert(sparsebit_is_clear(s, first) == !get_value(first));
+ break;
+ case 3:
+ if (sparsebit_any_set(s))
+ assert(get_value(sparsebit_first_set(s)));
+ if (sparsebit_any_clear(s))
+ assert(!get_value(sparsebit_first_clear(s)));
+ sparsebit_set_all(s);
+ assert(!sparsebit_any_clear(s));
+ assert(sparsebit_all_set(s));
+ num_ranges = 0;
+ ranges[num_ranges++] = (struct range)
+ { .first = 0, .last = ~(sparsebit_idx_t)0, .set = true };
+ break;
+ case 4:
+ if (sparsebit_any_set(s))
+ assert(get_value(sparsebit_first_set(s)));
+ if (sparsebit_any_clear(s))
+ assert(!get_value(sparsebit_first_clear(s)));
+ sparsebit_clear_all(s);
+ assert(!sparsebit_any_set(s));
+ assert(sparsebit_all_clear(s));
+ num_ranges = 0;
+ break;
+ case 5:
+ next = sparsebit_next_set(s, first);
+ assert(next == 0 || next > first);
+ assert(next == 0 || get_value(next));
+ break;
+ case 6:
+ next = sparsebit_next_clear(s, first);
+ assert(next == 0 || next > first);
+ assert(next == 0 || !get_value(next));
+ break;
+ case 7:
+ next = sparsebit_next_clear(s, first);
+ if (sparsebit_is_set_num(s, first, num)) {
+ assert(next == 0 || next > last);
+ if (first)
+ next = sparsebit_next_set(s, first - 1);
+ else if (sparsebit_any_set(s))
+ next = sparsebit_first_set(s);
+ else
+ return;
+ assert(next == first);
+ } else {
+ assert(sparsebit_is_clear(s, first) || next <= last);
+ }
+ break;
+ case 8:
+ next = sparsebit_next_set(s, first);
+ if (sparsebit_is_clear_num(s, first, num)) {
+ assert(next == 0 || next > last);
+ if (first)
+ next = sparsebit_next_clear(s, first - 1);
+ else if (sparsebit_any_clear(s))
+ next = sparsebit_first_clear(s);
+ else
+ return;
+ assert(next == first);
+ } else {
+ assert(sparsebit_is_set(s, first) || next <= last);
+ }
+ break;
+ case 9:
+ sparsebit_set_num(s, first, num);
+ assert(sparsebit_is_set_num(s, first, num));
+ assert(!sparsebit_is_clear_num(s, first, num));
+ assert(sparsebit_any_set(s));
+ assert(!sparsebit_all_clear(s));
+ if (num_ranges == 1000)
+ exit(0);
+ ranges[num_ranges++] = (struct range)
+ { .first = first, .last = last, .set = true };
+ break;
+ case 10:
+ sparsebit_clear_num(s, first, num);
+ assert(!sparsebit_is_set_num(s, first, num));
+ assert(sparsebit_is_clear_num(s, first, num));
+ assert(sparsebit_any_clear(s));
+ assert(!sparsebit_all_set(s));
+ if (num_ranges == 1000)
+ exit(0);
+ ranges[num_ranges++] = (struct range)
+ { .first = first, .last = last, .set = false };
+ break;
+ case 11:
+ sparsebit_validate_internal(s);
+ break;
+ default:
+ break;
+ }
+}
+
+unsigned char get8(void)
+{
+ int ch;
+
+ ch = getchar();
+ if (ch == EOF)
+ exit(0);
+ return ch;
+}
+
+uint64_t get64(void)
+{
+ uint64_t x;
+
+ x = get8();
+ x = (x << 8) | get8();
+ x = (x << 8) | get8();
+ x = (x << 8) | get8();
+ x = (x << 8) | get8();
+ x = (x << 8) | get8();
+ x = (x << 8) | get8();
+ return (x << 8) | get8();
+}
+
+int main(void)
+{
+ s = sparsebit_alloc();
+ for (;;) {
+ uint8_t op = get8() & 0xf;
+ uint64_t first = get64();
+ uint64_t last = get64();
+
+ operate(op, first, last);
+ }
+}
+#endif